sqlgraph

package
v0.7.0 Latest Latest
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 Go to latest Published: Mar 10, 2021 License: Apache-2.0 Imports: 12 Imported by: 2,845

Documentation

Overview

Package sqlgraph provides graph abstraction capabilities on top of sql-based databases for ent codegen.

Index

Constants

View Source 
const FuncSelector entql.Func = "func_selector"

FuncSelector represents a selector function to be used as an entql foreign-function.

Variables

This section is empty.

Functions

func BatchCreate 

func BatchCreate(ctx context.Context, drv dialect.Driver, spec *BatchCreateSpec) error

BatchCreate applies the BatchCreateSpec on the graph.

func CountNodes 

func CountNodes(ctx context.Context, drv dialect.Driver, spec *QuerySpec) (int, error)

CountNodes counts the nodes in the given graph query.

func CreateNode 

func CreateNode(ctx context.Context, drv dialect.Driver, spec *CreateSpec) error

CreateNode applies the CreateSpec on the graph.

func DeleteNodes 

func DeleteNodes(ctx context.Context, drv dialect.Driver, spec *DeleteSpec) (int, error)

DeleteNodes applies the DeleteSpec on the graph.

func HasNeighbors 

func HasNeighbors(q *sql.Selector, s *Step)

HasNeighbors applies on the given Selector a neighbors check.

func HasNeighborsWith 

func HasNeighborsWith(q *sql.Selector, s *Step, pred func(*sql.Selector))

HasNeighborsWith applies on the given Selector a neighbors check. The given predicate applies its filtering on the selector.

func IsConstraintError added in v0.7.0 

func IsConstraintError(err error) bool

IsConstraintError returns true if the error resulted from a DB constraint violation

func IsForeignKeyConstraintError added in v0.7.0 

func IsForeignKeyConstraintError(err error) bool

IsForeignKeyConstraintError reports if the error resulted from a DB FK constraint violation. e.g. parent row does not exist.

func IsUniqueConstraintError added in v0.7.0 

func IsUniqueConstraintError(err error) bool

IsUniqueConstraintError reports if the error resulted from a DB uniqueness constraint violation. e.g. duplicate value in unique index.

func Neighbors 

func Neighbors(dialect string, s *Step) (q *sql.Selector)

Neighbors returns a Selector for evaluating the path-step and getting the neighbors of one vertex.

func QueryEdges 

func QueryEdges(ctx context.Context, drv dialect.Driver, spec *EdgeQuerySpec) error

QueryEdges queries the edges in the graph and scans the result with the given dest function.

func QueryNodes 

func QueryNodes(ctx context.Context, drv dialect.Driver, spec *QuerySpec) error

QueryNodes queries the nodes in the graph query and scans them to the given values.

func SetNeighbors 

func SetNeighbors(dialect string, s *Step) (q *sql.Selector)

SetNeighbors returns a Selector for evaluating the path-step and getting the neighbors of set of vertices.

func UpdateNode 

func UpdateNode(ctx context.Context, drv dialect.Driver, spec *UpdateSpec) error

UpdateNode applies the UpdateSpec on one node in the graph.

func UpdateNodes 

func UpdateNodes(ctx context.Context, drv dialect.Driver, spec *UpdateSpec) (int, error)

UpdateNodes applies the UpdateSpec on a set of nodes in the graph.

func WrapFunc 

func WrapFunc(s func(*sql.Selector)) *entql.CallExpr

WrapFunc wraps a selector-func with an entql call expression.

Types

type BatchCreateSpec 

type BatchCreateSpec struct {
	Nodes []*CreateSpec
}

BatchCreateSpec holds the information for creating multiple nodes in the graph.

type ConstraintError 

type ConstraintError struct {
	// contains filtered or unexported fields
}

A ConstraintError represents an error from mutation that violates a specific constraint.

func (ConstraintError) Error 

func (e ConstraintError) Error() string

type CreateSpec 

type CreateSpec struct {
	Table  string
	Schema string
	ID     *FieldSpec
	Fields []*FieldSpec
	Edges  []*EdgeSpec
}

CreateSpec holds the information for creating a node in the graph.

type DeleteSpec 

type DeleteSpec struct {
	Node      *NodeSpec
	Predicate func(*sql.Selector)
}

DeleteSpec holds the information for delete one or more nodes in the graph.

type EdgeMut 

type EdgeMut struct {
	Add   []*EdgeSpec
	Clear []*EdgeSpec
}

EdgeMut defines edge mutations.

type EdgeQuerySpec 

type EdgeQuerySpec struct {
	Edge       *EdgeSpec
	Predicate  func(*sql.Selector)
	ScanValues func() [2]interface{}
	Assign     func(out, in interface{}) error
}

EdgeQuerySpec holds the information for querying edges in the graph.

type EdgeSpec 

type EdgeSpec struct {
	Rel     Rel
	Inverse bool
	Table   string
	Schema  string
	Columns []string
	Bidi    bool        // bidirectional edge.
	Target  *EdgeTarget // target nodes.
}

EdgeSpec holds the information for updating a field column in the database.

type EdgeSpecs 

type EdgeSpecs []*EdgeSpec

EdgeSpecs used for perform common operations on list of edges.

func (EdgeSpecs) FilterRel 

func (es EdgeSpecs) FilterRel(r Rel) EdgeSpecs

FilterRel returns edges for the given relation type.

func (EdgeSpecs) GroupRel 

func (es EdgeSpecs) GroupRel() map[Rel][]*EdgeSpec

GroupRel groups edges by their relation type.

func (EdgeSpecs) GroupTable 

func (es EdgeSpecs) GroupTable() map[string][]*EdgeSpec

GroupTable groups edges by their table name.

type EdgeTarget 

type EdgeTarget struct {
	Nodes  []driver.Value
	IDSpec *FieldSpec
}

EdgeTarget holds the information for the target nodes of an edge.

type FieldMut 

type FieldMut struct {
	Set   []*FieldSpec // field = ?
	Add   []*FieldSpec // field = field + ?
	Clear []*FieldSpec // field = NULL
}

FieldMut defines field mutations.

type FieldSpec 

type FieldSpec struct {
	Column string
	Type   field.Type
	Value  driver.Value // value to be stored.
}

FieldSpec holds the information for updating a field column in the database.

type Node 

type Node struct {
	NodeSpec

	// Type holds the node type (schema name).
	Type string

	// Fields maps from field names to their spec.
	Fields map[string]*FieldSpec

	// Edges maps from edge names to their spec.
	Edges map[string]struct {
		To   *Node
		Spec *EdgeSpec
	}
}

A Node in the graph holds the SQL information for an ent/schema.

type NodeSpec 

type NodeSpec struct {
	Table   string
	Schema  string
	Columns []string
	ID      *FieldSpec
}

NodeSpec defines the information for querying and decoding nodes in the graph.

type NotFoundError 

type NotFoundError struct {
	// contains filtered or unexported fields
}

NotFoundError returns when trying to update an entity and it was not found in the database.

func (*NotFoundError) Error 

func (e *NotFoundError) Error() string

type QuerySpec 

type QuerySpec struct {
	Node *NodeSpec     // Nodes info.
	From *sql.Selector // Optional query source (from path).

	Limit     int
	Offset    int
	Unique    bool
	Order     func(*sql.Selector)
	Predicate func(*sql.Selector)

	ScanValues func(columns []string) ([]interface{}, error)
	Assign     func(columns []string, values []interface{}) error
}

QuerySpec holds the information for querying nodes in the graph.

type Rel 

type Rel int

Rel is a relation type of an edge. 

const (
	O2O Rel // One to one / has one.
	O2M     // One to many / has many.
	M2O     // Many to one (inverse perspective for O2M).
	M2M     // Many to many.
)

Relation types.

func (Rel) String 

func (r Rel) String() (s string)

String returns the relation name.

type Schema 

type Schema struct {
	Nodes []*Node
}

A Schema holds a representation of ent/schema at runtime. Each Node represents a single schema-type and its relations in the graph (storage).

It is used for translating common graph traversal operations to the underlying SQL storage. For example, an operation like `has_edge(E)`, will be translated to an SQL lookup based on the relation type and the FK configuration.

func (*Schema) AddE 

func (g *Schema) AddE(name string, spec *EdgeSpec, from, to string) error

AddE adds an edge to the graph. It fails, if one of the node types is missing. 

g.AddE("pets", spec, "user", "pet")
g.AddE("friends", spec, "user", "user")

func (*Schema) EvalP 

func (g *Schema) EvalP(nodeType string, p entql.P, selector *sql.Selector) error

EvalP evaluates the entql predicate on the given selector (query builder).

func (*Schema) MustAddE 

func (g *Schema) MustAddE(name string, spec *EdgeSpec, from, to string)

MustAddE is like AddE but panics if the edge can be added to the graph.

type Step 

type Step struct {
	// From is the source of the step.
	From struct {
		// V can be either one vertex or set of vertices.
		// It can be a pre-processed step (sql.Query) or a simple Go type (integer or string).
		V interface{}
		// Table holds the table name of V (from).
		Table string
		// Column to join with. Usually the "id" column.
		Column string
	}
	// Edge holds the edge information for getting the neighbors.
	Edge struct {
		// Rel of the edge.
		Rel Rel
		// Schema is an optional name of the database
		// where the table is defined.
		Schema string
		// Table name of where this edge columns reside.
		Table string
		// Columns of the edge.
		// In O2O and M2O, it holds the foreign-key column. Hence, len == 1.
		// In M2M, it holds the primary-key columns of the join table. Hence, len == 2.
		Columns []string
		// Inverse indicates if the edge is an inverse edge.
		Inverse bool
	}
	// To is the dest of the path (the neighbors).
	To struct {
		// Table holds the table name of the neighbors (to).
		Table string
		// Schema is an optional name of the database
		// where the table is defined.
		Schema string
		// Column to join with. Usually the "id" column.
		Column string
	}
}

A Step provides a path-step information to the traversal functions.

func NewStep 

func NewStep(opts ...StepOption) *Step

NewStep gets list of options and returns a configured step. 

NewStep(
	From("table", "pk", V),
	To("table", "pk"),
	Edge("name", O2M, "fk"),
)

type StepOption 

type StepOption func(*Step)

StepOption allows configuring Steps using functional options.

func Edge 

func Edge(rel Rel, inverse bool, table string, columns ...string) StepOption

Edge sets the edge info for getting the neighbors.

func From 

func From(table, column string, v ...interface{}) StepOption

From sets the source of the step.

func To 

func To(table, column string) StepOption

To sets the destination of the step.

type UpdateSpec 

type UpdateSpec struct {
	Node      *NodeSpec
	Edges     EdgeMut
	Fields    FieldMut
	Predicate func(*sql.Selector)

	ScanValues func(columns []string) ([]interface{}, error)
	Assign     func(columns []string, values []interface{}) error
}

UpdateSpec holds the information for updating one or more nodes in the graph.

Source Files

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